问题 问答题

求过点P(1,0,7)且与平面x-z=10和y+2z=3都平行的直线方程.

答案

参考答案:

[考点点击] 本题考查直线与平面间的关系.

[要点透析] 两平面的法向量分别为n1={1,0,-1},n2={0,1,2}.

设所求直线的方向向量为v,由于直线与两平面都平行,所以v⊥n1且v⊥n2

v=n1×n2=={1,-2,1},

又直线过点P(1,0,7),则其对称式方程为

阅读理解

   Welcome to my Message Board!
Subject: Slimming down classics?
 
Mr.Handsome
2007-5-12
6: 34 AM
Orion Books, which decides there is a market in creating cut-down classics (经典著作), is slimming down some novels by such great writers as L. Tolstoy, M. Mitchell and C. Bronte. Now, each of them has been whittled down to about 400 pages by cutting 30 to 40 pages percent of original, with words, sentences, paragraphs and, in a few cases, chapters removed. The first six shortened editions, all priced at £6.99 and advertised as great reads “in half the time”, will go on sale next month, with plans for 50 to 100 more to follow. The publishing house believes that modern readers will welcome the shorter versions.  
 
Mr.Edwards
2007-5-12
9: 40 AM
Well, I’m publisher of Orion Group. Thanks for your attention, Mr. Handsome.
I must say, the idea developed from a game of “shame” in my office. Each of us was required to confess (承认) to the most embarrassing blanks in his or her reading. I admitted that I had never read Anna Karenina and tried but failed to get through Gone with the Wind several times. One of my colleagues acknowledged skipping (跳读) Jane Eyre. We realized that life is too short to read all the books you want to and we never were going to read these ones.
As a leading publishing house, we are trying to make classics convenient for readers but it’s not as if we’re withdrawing the original versions. They are still there if you want to read them.
Ms. Weir
2007-5-12
11:35 AM
I’m director of the online book club www.lovereading.co.uk
Mr. Edwards, I think your shortened edition is a breath of fresh air. I’m guilty of never having read Anna Karenina, because it’s just so long. I’d much rather read two 300-page books than one 600-page book. I am looking forward to more shortened classics!    
Mr.Crockatt
2007-5-12
4:38 PM
I’m from the London independent bookshop Corckatt & Powell.
In my opinion, the practice is completely ridiculous. How can you edit the classics? I’m afraid reading some of these books is hard work, and that is why you have to develop as a reader. If people don’t have time to read Anna Karenina, then fine. But don’t read a shortened version and kid yourself it’s the real thing.
11. According to the message board, Orion Books        .
A. opposes the reading of original classics          
B. is embarrassed for cutting down classics
C. thinks cut-down classics have a bright future      
D. is cautions in its decision to cut down classics
12. In Mr. Edwards’ opinion, Orion Group is shortening classics to        .
A. make them easier to read            B. meet a large demand in the market
C. increase the sales of literary books   D. compete with their original versions
13. By describing the shortened classics as “a breath of fresh air”, Ms. Weir        .
A. speaks highly of the cut-down classics     
B. shows her love for original classics
C. feels guilty of not reading the classics     
D. disapprove of shortening the classics
14. Mr. Crockatt seems to imply that        .
A. reading the classic works is a confusing attempt
B. shortening the classics does harm to the original
C. publishing the cut-down classics is a difficult job
D. editing the classic works satisfies children’s needs
15. How many classics are involved in the massage board?
A. Two.          B. Three.               C. Four.         D. Five.
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